ORIGINAL: Access
ORIGINAL: amen
Can someone explain the ratings on the esc, for ex Current some are rated at 35A and other at 100A. How can you choose the correct esc, does it go by the Amps on the motor; I'm asuming that the esc should be able to handle well over the motor requirments, is that correct?
25A to 35A is generally for 1/18th scale, 100A or more is generally for 1/10th scale. The given current rating is actually pretty arbitrary, there are many cases where companies over-rate their ESCs by 3x or even 4x their intended value.
A simple calculation you can do is look at the on-resistance and then apply a variant of Ohm's law
http://en.wikipedia.org/wiki/Resistor#Power_dissipation
Power = Current^2 * Resistance
This will give you a portion (not the whole) of heat that will be generated at the ESC when it actually passes through that much current.
So if you want to compare one ESC to the next, don't look at the current rating, look at the on-resistance and then the relative size of the heatsink, also consider whether it has a linear or a switching BEC.
Thanks for clearing that up!!